Method, apparatus and circuitry for droplet ejection

Abstract

A droplet ejection apparatus including a droplet deposition head, actuating circuitry and head controller circuitry. The droplet deposition head having an array of actuating elements and a corresponding array of nozzles. The actuating circuitry applies drive waveforms to the actuating elements causing the ejection of fluid in the form of droplets through the array of nozzles and onto deposition media, which are moved relative to the droplet deposition head. The head controller circuitry is configured to receive an input set of ejection data, generate a series of sub-sets of ejection data based on the input set, and send the series of sub-sets of ejection data to the actuating circuitry. The actuating circuitry is further configured so as to, for each sub-set of ejection data, apply drive waveforms to the actuating elements such that they repeatedly eject droplets from one or more nozzles, thus depositing successive rows of droplets. The one or more nozzles and the sizes of the droplets ejected therefrom are determined by the current sub-set of ejection data. Each of the one or more nozzles ejecting droplets with a substantially constant frequency of 1/T. The apparatus is further configured to receive deposition media speed data, which indicates the current speed of relative movement of the head with respect to the deposition media. The apparatus is further configured such that the head switches from ejecting droplets in accordance with a current sub-set of ejection data to ejecting droplets in accordance with a consecutive sub-set of ejection data in the series at a time determined in accordance with the media speed data, with the time interval between starting ejecting droplets in accordance with successive sub-sets of ejection data varying inversely with the current speed of relative movement of the droplet deposition head.